Manufacture of hydrogen peroxide



y 3, 1960 L. R. DARBEE EIAL 2,935,381

MANUFACTURE OF HYDROGEN PEROXIDE Filed April 19, 1957 t 2 Sec. Bu AQ InTNBP,-DMN

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LEONARD R. DARBEE g/1a PAUL 6. Co/waor @MM, Y @M,

ATTORNEYS.

United States Patent MANUFACTURE or HYDROGEN PEROXIDE Leonard R. Barbee,Grand Island, and Paul G. Conroy,

Bnlfalo, N.Y., assignors to Food Machinery and Chemical Corporation, SanJose, Calif.

Application April 19, 1957, Serial No. 653,972

3 Claims. (Cl. 23-207) This invention relates to the production ofhydrogen peroxide by an improvement in the so-called anthraquinoneprocess of manufacturing that product.

The ability of certain groups to undergo alternate hydrogenation andoxidation with the production of hydrogen peroxide has been known formany years. Commercial adaptation of these characteristic reactions isoutlined in Patents 2,158,525 and 2,215,883 of Pfleiderer and Riedlwherein it was proposed that the cyclic operation be performed in amixed solvent containing a solvent constituent for dissolving thequinone form of the working material, an alkylated anthraquinone or thetetrahydro derivatives thereof, and a solvent constituent for dissolvingthe hydroquinone form of the working material. A detailed analysis ofthe commercial operation of the anthraquinone process employing a mixedsolvent is outlined in a publication of thePublication Board, Departmentof Commerce, Washington, DC, PB Report 4336.

Subsequent investigators attempted to improve upon the process bysearching for solvents having greater dissolving power for the workingmaterial in the quinone form or hydroquinone form or both, and thesedevelopments are detailed in Patent 2,455,238 of Dawsey et al. showingthe employment of esters af sebasic acid, and in Patents 2,537,655 and2,537,516 of Dawsey et a1. showing the employment of organic phosphateesters and organic phosphonate esters respectively as improvedconstituents in a mixed solvent particularly adapted to dissolve thehydroquinone form of the working material.

Improved solubility of the working material was also made possible bythe employment of a mixed solvent containing certain aromatic solventsas a constituent for dissolving the quinone form of the workingmaterial, all as outlined in certain patents of Dawsey et al., No.2,768,065 and No. 2,768,066.

It will be noted from the above that substantially the entire researcheffort employed in improving the anthraquinone process of manufacturinghydrogen peroxide has been directed to the end that one would haveavailable better solvents for each form of the working material andemploying such solvents as constituents in the usual mixed solvent.

The approach to improving the anthraquinone process in all cases hasbeen an efiort to carry a greater amount of working material in a givenamount of working solution thereby proportionately to increase the yieldof hydrogen peroxide from a unit volume or amount of working solution.

In U.S. Patent No. 2,689,169 to Hinegardner, suggestions were madeallegedly for improving the amount of working material by selecting as aworking component an alkylated anthraquinone presumably producing agreater concentration in known solvents.

In Serial No. 618,069, filed October 24, 1956, by Leonard R. Darbee andDonald F. Kreuz, an approach was made for choosing special mixtures ofalkylated anthraquinones and their tetrahydro derivatives whichpossessed markedly greater solubility in known solvents,

such mixtures being compositions which are the eutectic mixtures ormixtures in the immediate neighborhood of such compositions.

The instant invention also deals with means for improving the solubilityof the working compound by employment of particular alkylatedanthraquinones and their tetrahydro derivatives in specified amounts ofsolvent, all to the end that the concentration in unit volume of workingsolution may be enhanced.

The particular advantages of the present invention are obtained byemploying as the working compound either preferably Z-Secondarybutylanthraquinone or Z-isopropylanthraquinone, as these two alkylatedanthraquinones possess a particular characteristic as to solvency whichappears not to be possessed by the other usually employed alkylatedanthraquinones, namely, the methyl, ethyl or tertiary butyl compounds.

The hydroquinone forms of methyl, ethyl and tertiary butylanthraquinones exhibit substantially no solvency in those solvents whichhave heretofore been designated quinone solvents. The quinone form ofmethyl, ethyl and tertiary butyl anthraquinone exhibit much less so1vency than their hydroquinone forms in solvents heretofore designated ashydroquinone solvents. It has now been found that this relationship inhydroquinone solvents is reversed in the case of the Z-secondary-butyland 2-isopropyl substituted compound. This relationship is strikinglyshown in Table 1 below, Where the figures given represent the number ofgrams of the indicated alkylated material soluble in 10 cc. of thespecified solvent at 25 C., where Q Form represents the quinone form andHQ the hydroquinone form of the specified alkylated Reference to Table 1above will show that when considered Z-tertiary butylanthraquinone itssolubility in the three specified organic phosphate esters normallyconsidered as solvents for the hydroquinone form of the working materialpossesses the normal characteristic expected, namely, a substantiallygreater solubility of the hydroquinone form than of the quinone form. Inthis respect the tertiary butylanthraquinone behaves in the same fashionas the methyl derivative and the ethyl derivative. Thus the solubilityof Z-tertiary butylanthraquinone in tri-n-butyl phosphate is 1.2 g. in10 cc. at 25 0, whereas that of tertiary butylanthrahydroquinone is 4.33g. in 10 cc. of that solvent at the same temperature, a solubilityadvantage of more than 3 /2 times with respect to the hydroquinone form.V

When considering the solubility of secondary butyl anthraquinonehowever, in the same solvent, the quinone form of that material is 5.5g. in 10 cc. of tri-n-butyl considering isopropyl anthraquinone.

"In accordance with the present invention considerable advantage inconcentration of working material is obtained when a working solutionfor use in the cyclic hydrogenation and oxidation to produce hydrogenperoxide is made up from either secondary butylanthraquinone,isopropylanthraquinone or mixtures thereof and particularly the eutecticmixture and to employers the working solvent either a mixed solvent or asingle solvent, the essential major constituent of which is a solventheretofore designated as a solvent for the hydroquinone form of theusual alkylated anthraquinones heretofore employed in the anthraquinoneprocess for the manufacture of hydrogen peroxide. Solvents of particularapplicability are the organic esters of phosphoric acid.

This same apparent reversal of solubility has been found to be presentin the case of the generally employed C-7 to Cll aliphatic alcohols, asfor instance the generally employed nonyl alcohols, alkyl cyclohexanolsand phosphonate esters, all generally considered'heretofore as solventsfor the hydroquinone form of the working material.

A simplified concept of the advantages of the invention may be obtainedby considering the solubility of the quinone form and hydroquinone formof secondary butyl anthraquinone in tri-n-butylphosphate. Under anoperating temperature of 25 C., 100 cc. of tri-n-butyl phosphate wouldcarry in solution 55 g. of the quinone form of working material andtherefore no additional solvent need be employed to carry the productproduced in the hydrogenation step of the anthraquinone process providedthe hydrogenation be not carried further than 60% 65x1 Table 2 belowsets forth the solubility in grams of the indicated alkylatedanthraquinone in dimethylnaphthalene, a solvent representative of aclass of solvents known as solvents for the quinone form of the workingmaterial and presently considereda solvent of particular advantage inthe mixed solvent process.

In the drawing the single figure shows the solubility of Z-secondarybutylanthraquinone in tri-n-butyl phosphate and dimethylnaphthalenemixtures. It will be noted that the hydroquinone form is insoluble indimethylnaphthalene, that is 0.0 gram, and is soluble to the extent of3.3 grams in 10 cc. of tri-n-butyl phosphate, while the quinone form ofthe secondary butyl derivative is soluble to the extent of g. in 10 cc.of dimethylnaphthalene at C. and to the extent of 5.5 g. in 10 cc. oftri-n-butyl phosphate.

A working solution containing 94.8% by volume of tri-n-butyl phosphateand 5.2% by volume of dimethylnaphthalene will carry as Working material6.24 g. 2- secondary butyl anthraquinone in 10 cc. Hydrogenating to 50%produces no cloud so that all the hydroquinone forms thereby producedremained soluble.

On subsequent oxidation and water extraction of the working solution, ayield of hydrogen peroxide of 0.267 g. is obtained, a yield equivalentto 26.7 g. per liter of working solution. This is in contrast to a yieldof 5.5 g. hydrogen peroxide per liter in the commercial operationdescribed in PB Report 4336, of 11 g. per liter as shown in U.S. PatentNo. 2,689,169, and 11.3 g. per liter as shown in U.S. Patent No.2,768,066.

A singular advantage of the present invention, as will be seen fromabove, resides in the very material reduction in amount of solvent andaccompanying increase in amount of working material capable of beingcarried and operated upon for the production of hydrogen peroxidethrough the hydrogenation cycle while maintaining each of the quinoneform and hydroquinone form in solution thereby increasing the productioncapacity of a given installation which consists of, in broad aspect atleast, a

, hydrogenating chamber or column, an oxidizing chamber or column and anextracting chamber or column or peroxide extractor where the hydrogenperoxide is extracted wizh water.

In the experimental data above, results have been shown in systemsemploying tri-n-butyl phosphate as the hydroquinone solvent anddimethylnaphthalene as the quinone solvent. It will be understood thatcomparable results can he obtained by using mixtures of solvents knownas hydroquinone solvents or mixtures of solvents known as quinonesolvents instead of the single species of each class as illustratedabove.

Additional data is shown below for various systems wherein the yield ofhydrogen peroxide is indicated at various depths of hydrogenation. Thereis also given the volume fraction of the working solution of specifiedsolvent for the hydroquinone form. In the instances shown below, thesolvent is constituted of di-isobutyl carbinol andalphamethylnaphthalene. The solubility of secondary butyl anthraquinonein 10 cc. of the specified solvent is given in the table below.

When secondary butylanthraquinone is employed in a mixed solvent ofalphamethylnaphthalene and di-isobutyl carbinol and the solutiondesignated worked at maximum capacity at 30 C., for the selected degreeof hydrogenation, the following yields of hydrogen peroxide areobtained:

Table 4 Volume Yield Hydro- Depth of Hydrogenation in Percent ofFraction gen Peroxide,

Complete Hydrogenation Di-isobutyl Grams H10 Carbinol per liter Table 5Compound Solvent Solubility Isopropylanthraquinone Dimethylnaphthalene..27% g. in

Do Tri-normal butyl phos- 4.35 g.in

phate. 10 cc.

Isopropylanthrahydroquinone Dimethylnaphthalene..- 0.01 g. in

000 Do Trl-normal butyl phos- 2.30 g. in

I phate. 10 cc.

in like manner, the system 2-secondary butyl anthraquinone as theworking compound in a working solution of d-irnethyl naphthalene andtri(2-ethyl hexyl)- phosphate worked to maximum capacity at 25 C. at thevarious selected depths of hydrogenation give the following results:

Table 7 Compound Solvent Solubility Secondary butylanthraqui-Dimethylnaphthalenc.. 20.0 g in none. 10 cc.

Do Tri-octyl phosphate 3.11%g. in

cc. Secondary butylanthrahydro- Dimethylnaphthaleno. 0.0 g. in

quinone. 10 cc.

Do Trl-octyl phosphate 1.89 g. in

Table 8 Volume Yield Hydro- Depth of Hydrogenation in Percent Fractiongen Peroxide,

Complete Hydrogenation 'Irl-octyl Grams H20; Phosphate per literPursuant to the requirements of the patent statutes, the principles ofthis invention have been explained and exemplified in a manner so thatit can be readily practiced by those skilled in the art, suchexemplification including what is considered to represent the bestembodiment of the invention. However, it should be clearly understoodthat, within the scope of the appended claims, the invention may bepracticed by those skilled in the art, and having the benefit of thisdisclosure, otherwise than as specifically described and exemplifiedherein.

What is claimed is:

1. In the process of producing hydrogen peroxide by the alternatereduction and oxidation of an alkylated anthraquinone as the workingmaterial dissolved in a mixed solvent containing a first constituent forsolution of both the hydroquinone form and the quinone form of theworking material, said first constituent being a solvent from the groupconsisting of the phosphate esters, the phosphonate esters, and the 0-7to C-ll aliphatic alcohols, and a second constituent in which thehydroquinone form is substantially insoluble for dissolving the quinoneform of the working material, the improvement which comprises employingas the working material an alkylated anthraquinone selected from thegroup consisting of 2- sccondary butyl anthraquinone and 2-isopropylanthraquinonc and a mixed solvent in which said first constituent ispresent to the extent of above 76 volume percent of the total amount ofsaid first constituent plus said second constituent, whereby the volumeof solvent is smaller than that heretofore employed.

2. Process in accordance with claim 1 in which the first constituent isan organic ester of phosphoric acid.

3. Process in accordance with claim 1 in which the first constituent isa 0-7 to C-ll aliphatic alcohol, and is present to the extent of above81 volume percent of the total amount of said first constituent plussaid second constituent.

References Cited in the file of this patent UNITED STATES PATENTS2,668,753 Harris ct al. Feb. 9, 1954 2,768,065 Dawsey et a1. Oct. 23,1956

1. IN THE PROCESS OF PRODUCING HYDROGEN PEROXIDE BY THE ALTERNATEREDUCTION AND OXIDATION OF A ALKYLATED ANTHRAQUINONE AS THE WORKINGMATERIAL DISSOLVED IN A MIXED SOLVENT CONTAINING A FIRST CONSTITUENT FORSOLUTION OF BOTH THE HYDROQUINONE FORM AND THE QUINONE FORM OF THEWORKING MATERIAL, SAID FIRST CONSTITUENT BEING A SOLVENT FROM THE GROUPCONSISTING OF THE PHOSPHATE ESTERS, THE PHOSPHONATE ESTERS, AND THE C-7TO C-11 ALIPHATIC ALCOHOLS, AND A SECOND CONSTITUENT IN WHICH THEHYDROQUINONE FORM IS SUBSTANTIALLY INSOLUBLE FOR DISSOLVING THE QUINONEFORM OF THE WORKING MATERIAL, THE IMPROVEMENT WHICH COMPRISES EMPLOYINGAS THE WORKING MATERIAL AN ALKYLATED ANTHRAQUINONE SELECTED FROM THEGROUP CONSISTING OF 2SECONDARY BUTYL ANTHRAQUINONE AND 2-ISOPROPYLANTHRAQUINONE AND A MIXED SOLVENT IN WHICH SAID FIRST CONSTITUENT ISPRESENT TO THE EXTENT OF ABOVE 76 VOLUME PERCENT OF THE TOTAL AMOUNT OFSAID FIRST CONSTITUENT PLUS SAID SECOND CONSTITUENT, WHEREBY THE VOLUMEOF SOLVENT IS SMALLER THAT THAT HERETOFORE EMPLOYED.